We request funds to purchase an automated crystallization system composed of an automatic liquid dispensing unit for screening crystallization conditions, a digital microscope camera stage for monitoring the crystallization experiments, and two temperature controlled crystallization incubators. The equipment will constitute a key addition to the capabilities of the Macromolecular Crystallography Core (MCC) in the Department of Biochemistry and Molecular Biophysics (BMB). It will support six major users pursuing NIH-supported projects in structural biology and drug discovery, and will be available for other minor users as well. Senior research scientists of the MCC will provide oversight of the instrument, training, and assistance to users. Currently, all crystallization screening and optimization experiments in the MCC are conducted manually. This material-consuming and labor-intensive method, which requires hundreds of similar screening experiments, constitutes a major shortcoming in the production of diffraction- quality crystals of macromolecules and their ligand complexes. Recent developments in automation and miniaturization technology have helped to overcome these limitations and have proven to be very successful in obtaining crystals of new proteins or new protein complexes. Automation of the screening process increases throughput and improves reproducibility, while miniaturization reduces the cost of the experiment by allowing much smaller volumes of difficult- to-obtain protein and screening solutions to be used. The requested equipment will lead to substantially more crystals of difficult-to-crystallize proteins, to more structures of protein- inhibitor complexes identified through drug discovery screens, and will lower the barrier for non- experts to enter the field of structural biology. HEALTH RELEVANCE: Structural biology is a powerful tool for uncovering mechanism in disease and new targets for drug discovery. Structure-based drug design represents one of the most successful paths to new treatments. The proposed instrument will help overcome a bottleneck in these approaches by automating and reducing the quantities of precious materials needed for successful crystallographic studies at the University of Arizona.